Prepared by :

Jay Patel (110750106006)

Malay Patel (110750106024)

Kushagra Rawal (110750106028)

What is Beam-Column Joint ?

Types & Importance of Beam-Column Joint

Earthquake Behaviour of Joints

Reinforcing of Beam-column Joints

How to provide Horizontal ties in beams ?

Anchorage of beam bars

Exterior joint

Interior Joints

In RC buildings, portions of columns that are common to beams attheir intersections are called beam- column joints.

Since their constituent materials have limitedstrengths, the joints have limited force carrying capacity.

When forces larger than these are applied duringearthquakes, joints are severely damaged.

Repairing damaged joints is difficult, and so damagemust be avoided. Thus, beam-column joints must bedesigned to resist earthquake effects.

Under earthquake shaking, the beams adjoining a joint aresubjected to moments in the same (clockwise or counter-clockwise) direction .

Under these moments, the top bars in the beam-column joint arepulled in one direction and the bottom ones in the oppositedirection .

If the column is not wide enough or if the strength of concrete inthe joint is low, there is insufficient grip of concrete on the steelbars.

In such circumstances, the bar slips inside the joint region, andbeams loose their capacity to carry load.

Further, under the action of the above pull-push forces at top and bottom endsone diagonal length of the joint elongates and the other compresses . If thecolumn cross-sectional size is insufficient, the concrete in the joint developsdiagonal cracks.

Diagonal cracking & crushing ofconcrete can be prevented in Joints.

Mostly, for this large column size isthe most effective.

Another way is providing steel tiesalso known as stirrups.

Providing closed loop ties needs some extra effort.

Indian Standard IS:13920-1993 recommends continuing thetransverse loops around the column bars through the jointregion.

In practice, this is achieved by preparing the cage of thereinforcement (both longitudinal bars and stirrups) of all beamsat a floor level to be prepared on top of the beam formwork ofthat level and lowered into the cage .

However, this may not always be possible particularly when thebeams are long and the entire reinforcement cage becomesheavy.